CN1926698B - Deposition of Conductive Polymers - Google Patents

Abstract

A precipitant is deposited on the bottom electrode layer of the organic electronic device prior to the preparation of the organic layer. After depositing the precipitating agent, an organic material is deposited over the precipitating agent. Precipitating agents result in a more uniform and even profile when drying the organic material into a film on the treated surface.

Description

Deposition of Conductive Polymers

technical field

The present invention generally relates to the field of thin film device processing and fabrication. More specifically, the present invention relates to the fabrication of OLED-based displays and other electronic devices using selective deposition.

Background technique

Displays and lighting systems based on LEDs (Light Emitting Diodes) have a variety of applications. Such displays and lighting systems are designed by arranging a plurality of optoelectronic elements ("elements"), such as arrays of individual LEDs. LEDs based on semiconductor technology have traditionally used inorganic materials, but recently, organic LEDs ("OLEDs") have become popular for certain applications. Examples of other elements/devices using organic materials include organic solar cells, organic transistors, organic detectors, and organic lasers. There are also many biotechnological applications, such as biochips for DNA recognition utilizing organic materials, combinatorial synthesis, etc.

A typical OLED comprises two or more thin, at least partially conductive organic layers (eg, a conductive hole transport polymer layer (HTL) and an emissive polymer layer, where the emissive polymer layer emits light) sandwiched between an anode and a cathode. . At an applied positive potential, the anode injects holes into the conducting polymer layer and the cathode injects electrons into the emissive polymer layer. The injected holes and electrons each move towards oppositely charged electrodes and recombine to form excitons in the emissive polymer layer. By emitting radiation and processing, the excitons return to a lower energy state and emit light.

Other organic electronic devices, such as organic transistors and organic sensors, generally also contain conductive organic (polymer) layers and other organic layers. Many of these OLEDs or other organic electronic devices can be arranged in a pattern on a substrate, for example in a display system. One way of patterning organic electronic devices on top of a substrate is to create pockets by photolithography, followed by a process known as inkjet printing. The use of a photoresist layer to define pockets for inkjet printing is disclosed in published patent application number US2002/0060518A1 entitled "Organic Electroluminescent Device and Method of Manufacturing Thereof". In inkjet printing, a polymer or organic solution is deposited by discharging multiple drops of the solution from a printhead into a bag. One common application of inkjet printing is patterning multi-color OLED pixels (eg RGB patterned pixels) to make color displays.

Figure 1 shows a prior art inkjet printing system for depositing a solution. In FIG. 1 , an OLED display being fabricated includes a substrate 109 and an anode 112 on the substrate 109 . A bank structure 115 is located on the anode 112; the bank structure has a hole 118 through which the anode is exposed (the hole 118 may be a pocket or a wire). The HTL 121 is located on the exposed portion of the anode 112. An emissive polymer layer 122 is on the HTL 121. Here, the emissive polymer layer 122 is formed by discharging a solution drop 124 including the emissive polymer onto the HTL, and then drying the emissive polymer solution. The emissive polymer solution is discharged through the nozzles 127 of the printhead 130 . Even if emissive polymer layers 122 have a flat or uniform drying profile, if they are deposited directly on anode 112, the presence of HTL 121 will affect their profile as they are dried on top of HTL 121. It is therefore important that both the HTL 121 and the emissive polymer layer have a flat uniform profile. In the current state of the art, HTL 121 generally has a very uneven and concave profile, as shown in Fig. 2(a).

As can be observed, the dried pattern was quite uneven and showed build-up on the edge of the drop 200 representing a drop of conductive polymer solution. This is due to differences in evaporation rates at different regions of the drop 200, creating surface tension variations which in turn cause species to move from the center towards the edges of the drop 200, thus ultimately depositing more material at the edges than at the center. This phenomenon is commonly referred to as the Marangoni effect. A common example of this phenomenon is a dry coffee stain, which appears to be more prominent (darker in color) at the edges of the spot than in the center.

While there is a normal sloping photoresist patch as in the case of drop 210, the profile of drop 210 is still substantially non-uniform when dry. There is buildup at the edges affecting the useful part of the device. As the thickness of the dried film increases and becomes more non-uniform, the current through that portion of the film decreases, resulting in less light being emitted from those portions. This is because the electrical properties do not remain very constant in non-uniform regions of the film. This would leave fewer films that are practically usable in terms of acceptable device performance, as shown.

Figure 2(b) shows the forces associated with a liquid solution on a dry surface. As shown, the liquid solution contains very fine particles (small molecules) that have negligible gravitational effects pulling the solution towards the surface. At the edges of the drops, capillary and surface tension pulls on the drops tend to pull the solution towards the edges, which leads to a build-up of dried material at those edges. When the film dries, the profile is not very uniform due to the Marangoni effect and is much thicker at the edges than in the center as shown.

It would be desirable to produce conductive polymer films that are more uniform in thickness and thus have a flatter profile than is typically observed for conductive polymer films.

Contents of the invention

According to the invention, a precipitating agent is deposited on the lower electrode layer of the organic electronic device prior to the preparation of the organic layer. After depositing the precipitating agent, an organic material is deposited over the precipitating agent. Precipitating agents result in a more uniform and even profile as the organic material dries into a film on the treated surface.

In one embodiment of the invention, the precipitating agent is spin-coated onto the lower electrode layer. In the case of OLEDs which are bottom emitting, the bottom electrode layer serves as the anode and the organic material is a conductive polymer solution. The organic material is deposited over the precipitating agent, and in some cases, may be selectively deposited by inkjet printing techniques. In embodiments where the organic material is to be inkjet printed into pockets formed over the lower electrode layer, the precipitating agent may also be printed rather than spin coated.

Brief introduction to the drawings

Figure 1 illustrates an example of an inkjet printing system used to prepare a patterned surface.

Figure 2(a) illustrates the drying pattern of a liquid substance when the substance is dropped with and without photoresist.

Figure 2(b) shows the forces associated with a liquid solution on a dry surface.

Figure 3(a) illustrates the forces associated with drying a drop of organic solution deposited on and dissolved in a precipitant.

Figure 3(b) illustrates the resulting drying profile of a drop of organic solution deposited on and dissolved in a precipitating agent.

Figure 3(c) illustrates a printing process utilizing a precipitation agent according to the present invention.

Figure 4 illustrates a cross-section of the layers of an OLED device according to the invention.

Fig. 5 shows the workflow of OLED preparation using precipitating agent according to the present invention.

Detailed ways

According to the present invention, the drying profile of the deposited organic (eg, conductive polymer) solution is altered by depositing a precipitant on the deposition surface prior to depositing the organic solution. Precipitating agents cause a more uniform and flatter profile when the organic solution dries into a film on the treated surface. In the case of OLED devices, the precipitant is deposited on the lower electrode layer, which in bottom-emitting OLEDs is the anode. The use of a precipitant produces a substantially uniform and planar profile for a conductive polymer or other organic layer formed by drying an organic solution deposited on the device (over the precipitant).

Precipitating agents can be deposited in a variety of ways including, but not limited to, spin coating, dip coating, and inkjet printing. Precipitating agents are preferably 1) soluble in water or water-based media, 2) have a solubility of 30% or greater, 3) have a high boiling point to prevent rapid evaporation, and 4) have minimal reactivity with organic solutions. The precipitating agent causes the particles of the organic solution to become "heavy" or larger in size so that the effect of gravity is greater. The added gravitational effect will compensate capillary and surface tension in a better way. This in turn will pull more of the molecules of the organic solution in a direction perpendicular to the deposition surface rather than parallel to it. This reduces movement of the solution towards the edges while drying, thereby resulting in a flatter and more uniform film.

In some embodiments of the present invention, a process for fabricating an organic electronic device is disclosed whereby 1) a precipitating agent is deposited on a deposition surface, and 2) an organic solution is deposited over the precipitating agent. The precipitating agent combines with the deposited organic solution and dissolves in this solution. The organic solution is allowed to evaporate and dry to a film with a substantially flat and uniform profile. After drying the organic layer, other steps are performed to complete the organic electronic device fabrication. Examples of organic electronic devices thus prepared include OLEDs, organic transistors, organic solar cells, and the like.

In one embodiment of the present invention, the precipitating agent used is propylene carbonate with a boiling point of about 240 degrees Celsius. In other embodiments of the invention, the precipitating agent used is benzyl alcohol with a boiling point of about 205 degrees Celsius. In other embodiments of the invention, the precipitating agent used is dioxane having a boiling point between about 100-102 degrees Celsius. In other embodiments of the invention, the precipitating agent may comprise a divalent cation salt solution.

Figure 3(a) illustrates the forces associated with the drying of an organic solution droplet deposited on and dissolved in a precipitating agent. According to the present invention, a drop 300 of organic solution is deposited on a precipitating agent (not shown separately) dissolved therein. As shown in FIG. 3( a), the precipitating agent causes the particles of the drop to become large in size and bond together to increase their weight and the influence of gravity on them, thereby moving in a direction normal to the deposition surface 310. pull them down. This will at least partially compensate for the effects of capillary and surface tension which tend to pull the particles of the solution towards the edge of the deposited drop 300 .

Figure 3(b) illustrates the resulting drying profile of a drop of organic solution deposited on and dissolved in a precipitating agent. As shown, the drop dried into film 305 exhibits a flatter, uniform profile. More notably, as described above, solution build-up towards the edges of the dry film 305 is significantly reduced.

Figure 3(c) illustrates a printing process using a precipitation agent according to the present invention. Precipitating agent 320 is deposited into pockets shown defined by photoresist structures 330 prepared above the deposition surface. After depositing precipitating agent 320 , one or more drops of organic solution (not labeled) are deposited onto precipitating agent 320 . Mixing of the organic solution with the precipitating agent 320 causes the particles of the solution to combine and grow larger. The large particle size helps to change the directional dynamics of drying so that the solution dries less than normal at the edge of the drop. Due to this interaction the solution dries to a uniform flat film 340, as shown. In this example it is assumed that the solution expands or has a volume large enough to contact the walls of photoresist structure 330, as shown. The organic solution can be a single drop or a sequence of individual drops joined together into a mass, depending on the volume of the liquid, the printing technique used, etc.

In one embodiment of the invention where the fabricated device is an OLED, the organic solution can be prepared from, for example, polyethylene dioxide thiophene ("PEDOT") and polystyrene sulfonic acid ("PSS") (hereinafter "PEDOT:PSS solution") ) to form a conductive polymer solution. For bottom emitting OLED devices, the deposition surface is the surface of the anode layer, eg comprising ITO (Indium Tin Oxide). Examples of precipitants, PEDOT:PSS, and other organic solutions and deposition surfaces are discussed below.

FIG. 4 shows a cross-sectional view of an embodiment of an organic electronic device 405 according to the invention. As shown in FIG. 4 , the organic electronic device 405 includes a first electrode 411 on a substrate 408 . As used in the specification and claims, the term "on" includes both instances where multiple layers are in physical contact as well as instances where multiple layers are separated by one or more intervening layers. The first electrode 411 may be patterned for pixilated applications, or unpatterned for backlight applications. If the electronic device 405 is a transistor, the first electrode may eg be the source and drain contacts of said transistor. A photoresist material is deposited on the first electrode 411 and patterned to form a bank structure 414 having holes exposing the first electrode 411 . The holes can be pockets (eg, pixels of an OLED display) or lines. The dike structure 414 is an insulating structure that electrically isolates one pocket from another, or one line from another.

One or more organic materials are deposited into the holes to form one or more organic layers of organic stack 416 . The organic stack 416 is located on the first electrode 411 . The organic stack 416 includes a hole transport (conductive polymer) layer (“HTL”) 417 and an otherwise active electron layer 420 . If the first electrode 411 is an anode, the HTL 417 is located on the first electrode 411. Alternatively, if the first electrode is a cathode, the active electron layer 420 is located on the first electrode 411, and the HTL 417 is located on the active electron layer 420. The electronic device 405 also includes a second electrode 423 on the organic stack 416 . If the electronic device 405 is a transistor, the second electrode 423 may eg be a gate contact of said transistor. Other layers than those shown in FIG. 4 may also be added, including insulating layers between the first electrode 411 and the organic stack 416 , and/or between the organic stack 416 and the second electrode 423 . Some of these layers according to the invention are described in more detail below.

Substrate 408:

Substrate 408 may be any material that can support organic and metal layers thereon. Substrate 408 may be transparent or opaque (eg, opaque substrates are used in top emitting devices). By changing or filtering the wavelengths of light that can pass through substrate 408, the color of light emitted by the device can be changed. Substrate 408 may comprise glass, quartz, silicon, plastic, or stainless steel; preferably, substrate 408 comprises thin, flexible glass. The preferred thickness of substrate 408 depends on the materials used and the application of the device. Substrate 408 may be in the form of a thin sheet or a continuous film. For example, continuous films can be used in roll-to-roll manufacturing processes, which are especially suitable for plastic, metal and metallized plastic foils. The substrate may also have built-in transistors or other switching elements to control the operation of the device.

The first electrode 411:

In one configuration, the first electrode 411 serves as an anode (an anode is a conductive layer that acts as a hole injection layer and includes a material with a work function greater than about 4.5 eV). Typical anode materials include metals (such as platinum, gold, palladium, indium, etc.); metal oxides (such as lead oxide, tin oxide, ITO, etc.); graphite; doped inorganic semiconductors (such as silicon, germanium, gallium arsenide, etc. ); and doped conductive polymers (such as polyaniline, polypyrrole, polythiophene, etc.).

The first electrode 411 may be transparent, translucent, or opaque to the wavelength of light generated within the device. The thickness of the first electrode 411 is from about 10 nm to about 1000 nm, preferably from about 50 nm to about 200 nm, more preferably about 100 nm. The first electrode 411 can generally be prepared using any of the techniques known in the art for depositing thin films including, for example, vacuum evaporation, sputtering, electron beam deposition, or chemical vapor deposition.

In an alternative structure, the first electrode layer 411 is used as a cathode (a cathode is a conductive layer that acts as an electron injection layer and includes a material with a low work function). In the case of eg a top emitting OLED, the cathode, rather than the anode, is deposited on the substrate 408 . Typical cathode materials are listed below in the section "Second Electrode 423".

Dike Structures 414:

The bank structure 414 is made of a photoresist material such as polyimide or polysiloxane. The photoresist material may be a positive photoresist material or a negative photoresist material. The dike structure 414 is an insulating structure that electrically isolates one pocket from another, or one line from another. The bank structure 414 has a hole 415 exposing the first electrode 411 . Holes 415 may represent pockets or threads. The bank structure 414 is patterned by applying photolithographic techniques to a photoresist material or by depositing bulk material in a desired pattern using screen printing or flexographic printing. As shown in FIG. 4 , the bank structure 414 may have, for example, a trapezoidal structure in which an angle between a sidewall of the bank structure 414 and the first electrode 411 is an obtuse angle. Alternatively, the dike structure may be semicircular or curved in practice.

HTL 417:

The HTL 417 has a higher hole mobility than electron mobility and serves to efficiently transport holes from the first electrode 411 to the substantially uniform organic polymer layer 420. HTL 417 is made of polymer or small molecule material. For example, HTL 417 can be made from tertiary amine or carbazole derivatives, conductive polyaniline ("PANI") or PEDOT:PSS in the form of small molecules or polymers. HTL 417 has a thickness of from about 5 nm to about 1000 nm, preferably from about 20 nm to about 500 nm, and more preferably from about 50 to about 250 nm.

HTL 417 is used as: (1) a buffer to provide good bonding to the substrate; and/or (2) a hole injection layer to facilitate hole injection; and/or (3) a hole transport layer to facilitate hole injection Cave transmission.

HTL 417 can be deposited using selective deposition techniques or non-selective deposition techniques. Examples of alternative deposition techniques include, for example, inkjet printing, flex printing, and screen printing. Examples of non-selective deposition techniques include, for example, spin coating, dip coating, web coating, and spray coating. If printing techniques are used, the hole transport material is deposited on the first electrode 411 and then allowed to dry. The dried material represents the hole transport layer.

As described above, according to the present invention, a precipitant is deposited on the first electrode layer 411 prior to any deposition of organic materials used to form the HTL 417. An example of a typical HTL material is a PEDOT:PSS solution, such as Baytron PAI4083, which has a ratio of one part to six parts PEDOT to PSS. Addition of a precipitant on the first electrode 411 prior to deposition of the HTL material produces a dried HTL 417 that is more uniform and flat in profile than is typical. The use of Baytron P AI4083 manufactured by H.C. Starck, a division of Bayer AG is however only exemplary.

The present invention can be used to provide a flat and uniform drying profile of any PEDOT:PSS solution or any organic solution by depositing a precipitating agent on the surface (eg first electrode 411 ) on which the solution is to be dried. Exemplary precipitants that can be deposited for conducting polymer solutions are: 1) dioxane with a boiling point around 100-102°C, 2) propylene carbonate with a boiling point around 240°C, 3) a boiling point around 205°C Benzyl alcohol, and 4) high concentrations of divalent cation salts, such as calcium chloride and/or magnesium sulfate, as long as the salt is water soluble so as to cause precipitation.

Active electronic layer 420:

The active electron layer 420 may include one or more layers. The active electronic layer 420 includes active electronic materials. The active electronic material may comprise a single active electronic material, a combination of active electronic materials, or multiple layers of single or combined active electronic materials. Preferably, at least one active electronic material is organic.

For an organic LED (OLED), the active electronic layer 316 includes at least one light-emitting organic material. These organic light-emitting materials are generally classified into two types. The first type of OLED, known as a polymeric light emitting diode or PLED, utilizes a polymer as part of the active electronic layer 420 . In practice, polymers can be organic or organometallic. As used herein, the term "organic" also includes organometallic materials. Preferably, the polymers are solvated in an organic solvent, such as toluene or xylene, and spin-coated onto the device, although other methods are possible. Devices utilizing polymeric active electronic material in the active electronic layer 316 are especially preferred. In addition to materials that emit light, active electronic layer 420 may also include photoresponsive materials that change their electrical properties in response to light absorption. Typically photoresponsive materials are used in detectors and solar panels that convert light energy into electricity.

If the organic electronic device is an OLED or an organic laser, the organic polymer is an electroluminescent ("EL") polymer that emits light. The light-emitting organic polymer can be, for example, an EL polymer having conjugated repeat units, especially EL polymers in which adjacent repeat units are joined in a conjugated form, such as polythiophene, polyphenylene, polythiophenevinylene, Or poly-p-phenylene vinylene or their congeners, copolymers, derivatives or mixtures thereof. More specifically, the organic polymer may be, for example: polyfluorene; poly-p - phenylene vinylene; polyspiro polymer.

If the organic electronic device is an organic solar cell or an organic photodetector, an organic polymer is a photoresponsive material that changes its electrical properties in response to light absorption. Photoresponsive materials convert light energy into electrical energy.

If the organic electronic device is an organic transistor, the organic polymer can be, for example, a polymeric and/or oligomeric semiconductor. Polymeric semiconductors may include, for example, polythiophene, poly(3-alkyl)thiophene, polythienylvinylene, poly(p-phenylenevinylene), or polyfluorene or their congeners, copolymers, derivatives, or mixtures thereof .

In addition to polymers, small organic molecules that fluoresce or phosphoresce can be used as light emitting materials present in the active electronic layer 316 . Unlike polymeric materials applied as solutions or suspensions, small molecule luminescent materials are preferably deposited by evaporation, sublimation or organic vapor deposition. Combinations of PLED materials and small organic molecules can also serve as active electronic layers. For example, a PLED may be chemically derivatized or simply mixed with small organic molecules to form the active electron layer 316 .

The active electronic layer 420 may include materials capable of charge transport in addition to light-emitting active electronic materials. Charge transport materials include polymers or small molecules that can transport charge carriers. For example, organic materials such as polythiophenes, derivatized polythiophenes, oligothiophenes, derivatized oligopolythiophenes, pentacene, compositions including C60, and compositions including derivatized C60 may be used. The active electronic layer 420 may also include a semiconductor such as silicon or gallium arsenide.

Second electrode (423):

In one embodiment, the second electrode 423 acts as a cathode when a potential is applied across the first electrode 411 and the second electrode 423 . In this embodiment, when a potential is applied across the first electrode 411 serving as an anode and the second electrode 423 serving as a cathode, photons are released from the active electron layer 420, passing through the first electrode 411 and the substrate. Bottom 408.

While many materials that can be used as cathodes are known to those skilled in the art, it is most preferred to use a combination comprising aluminum, indium, silver, gold, magnesium, calcium and barium, or combinations thereof, or alloys thereof.

Preferably, the thickness of the second electrode 423 is from about 10 to about 1000 nanometers (nm), more preferably from about 50 to about 500 nm, most preferably from about 100 to about 300 nm. While many methods are known to those of ordinary skill in the art by which the first electrode material can be deposited, vacuum deposition methods such as physical vapor deposition (PVD) are preferred. Other layers (not shown), such as barrier layers and getter layers, may also be used to protect the electronics. These layers are well known in the art and are not specifically discussed here.

Fig. 5 shows the workflow for fabricating organic electronic devices according to the present invention. First, a bottom electrode layer is prepared/patterned over a substrate (step 510). In the case of OLED devices, the lower electrode layer is preferably used as anode. Typical anode materials include metals (e.g., aluminum, silver, copper, indium, tungsten, lead, etc.); metal oxides; graphite; doped inorganic semiconductors (e.g., doped silicon, gallium arsenide, etc.); Conductive polymers (such as polyaniline, polythiophene, etc.). For OLEDs, the bottom electrode layer is generally thin enough to be semi-transparent and transmit at least some light (in bottom emitting OLEDs). Likewise, any thin film deposition method may be used in the preparation step 510 . These include, but are not limited to, vacuum evaporation, sputtering, electron beam deposition, chemical vapor deposition, etching and other techniques known in the art and combinations thereof. Typically the process also includes a baking or annealing step under controlled atmosphere to optimize the conductivity and light transmission of the anode layer. Photolithography can then be used to define arbitrary patterns in the lower electrode layer.

The next step is to add photoresist bank structures to define pockets in the anode layer (step 520). Photoresist banks are prepared by applying photolithographic techniques to the photoresist material (or by using screen printing or flexographic printing to deposit the bank material in the desired pattern). Photoresist materials are generally classified into two types, positive or negative. Positive photoresists are photoresists that dissolve where exposed to light. Negative photoresist is photoresist that dissolves everywhere except where it is exposed to light. Positive or negative photoresist can be used as desired in forming the photoresist banks. Photoresist chemistry and processes such as lithography, baking, development, etching, and radiation exposure that can be used to pattern photoresist into banks are well known to those skilled in the art.

According to the present invention, the next step is to deposit a precipitation agent into the pocket defined by the photoresist structure (step 525). The precipitating agent will change the molecular properties of the conductive polymer solution that follows it, making the molecules larger and more susceptible to gravity. In one embodiment of the invention, the precipitant is printed using a selective deposition technique. In an alternative embodiment of the present invention, step 525 may replace the previous step 520 to deposit a precipitant prior to preparing the photoresist structure. In these embodiments, the precipitant may be deposited by spin coating or dipped/rolled.

Next, a conductive polymer layer is printed by depositing a conductive polymer solution over the precipitating agent (step 530). The conductive polymer layer is preferably applied using printing techniques such as inkjet printing (screen printing, flexographic printing). In particular, in this case a conductive polymer layer is printed inside pockets defined by banks of photoresist. The conductive polymer layer is printed by depositing an organic solution into a pocket over a precipitating agent and allowing the mixture to dry. The dry film then represents the conductive polymer layer. The addition of a precipitating agent enables the conductive polymer layer to have a uniform and flat profile after drying is complete. The conductive polymer layer is also referred to as a hole transport layer ("HTL"). Conductive polymer layers are used to improve, for example, charge balance, display stability, turn-on voltage, display brightness, display efficiency, and display lifetime. The conductive polymer layer serves to enhance the hole flux of the OLED relative to the potential applied across it, thereby facilitating more energy-efficient injection of holes into the emissive polymer layer for recombination.

Then according to step 535, the emissive polymer layer is printed. The emissive polymer layer is primarily responsible for emitting light from the OLED, and is thus an electroluminescent, semiconducting and organic (organo-metallic) type of material as discussed above. In inkjet printing, a variety of different emissive polymeric substances are possible. For example, in the printhead there may be red, green and blue light emitting polymers deposited depending on the desired color to be emitted in a given pixel location defined by the pocket. The emissive polymer substance is deposited on the conductive polymer layer by a print head in precise areas defined by the pockets. The emissive polymer layer results from the drying of the material deposited by the print head.

The conductive polymer layer and the emissive polymer layer can be printed by depositing a liquid solution between layers of photoresist that define pockets. The liquid solution may be any "fluid" or deformable mass capable of flowing under pressure, and may include solutions, inks, pastes, latexes, dispersions, and the like. The liquid also contains or is supplemented by other substances that affect the viscosity, contact angle, thickening, affinity, drying, dilution, etc. of the deposited droplet.

After printing the emissive polymer layer, a top electrode layer is formed/deposited (step 540). In an OLED device, the upper electrode layer acts as the cathode (if the lower electrode layer is the anode). Cathode layer materials are discussed above. An insulating material such as LiF, NaF, CsF, etc. may also be used under the upper electrode layer to enhance implantation by tunneling. The lower electrode layer is typically formed/deposited using vacuum evaporation or similar techniques and often using specially designed deposition equipment. Other steps such as adding a mask and photoresist can typically be performed prior to cathode deposition step 540 . However, these are not specifically listed as they do not specifically relate to the novel aspects of the invention. Other steps (not shown) may also be included in the workflow, such as adding a metal wire connecting the anode wire and the power supply. The workflow of Figure 5 is not intended to be all inclusive and is merely exemplary. For example, after an OLED is fabricated, it is typically encapsulated to protect the layers from environmental damage or exposure. These other processing steps are well known in the art and are not the subject of the present invention.

The introduction of a precipitating agent can be used to provide a flat and uniform drying profile of any conductive polymer solution or any organic solution deposited thereon. Thus the present invention is not limited to any one type of precipitant or deposition solution.

While embodiments of the invention are described where it is primarily incorporated within OLED displays, virtually any type of electronic device using dry film layers may be a possible application for these embodiments. In particular, the invention can also be used in solar cells, transistors, phototransistors, lasers, photodetectors, or optocouplers. It can also be used in biological applications (such as biosensors) or chemical applications (such as applications in combinatorial synthesis, etc.). The OLED displays described earlier can be used in displays in applications such as computer monitors, information displays for vehicles, television monitors, telephones, printing presses, and illuminated signs.

Claims (13)

1. method for preparing organic electronic device, described method comprises:

Go up patterning lower electrode layer (411) at substrate (408), described lower electrode layer has the surface that the top exposes;

Deposition sedimentation agent (320) on described lower electrode layer;

On described precipitation reagent, deposit organic solution (300), wherein said organic solution causes the particle of described solution to combine and becomes bigger dimensionally with precipitant mix, so that increase their weight and the influence of the gravity on them, thereby with the particle of described organic solution to be orthogonal to the drawing that is directed downwards of described lower electrode layer, and the described mixture of described organic solution and described precipitation reagent is dried to organic layer (305), described organic layer has a substantially flat and profile uniformly.

2. according to the process of claim 1 wherein by the described precipitation reagent of spin-on deposition (320).

3. according to the process of claim 1 wherein that described organic electronic device is Organic Light Emitting Diode (OLED) display.

4. according to the method for claim 3, wherein said lower electrode layer (411) is as anode.

5. according to the method for claim 4, wherein said organic layer (305) is conductive polymer coating (417).

6. according to the method for claim 5, also comprise:

Prepare emission layer on described conductive polymer coating (417), described emission layer is luminous when charge recombination.

7. according to the method for claim 6, also comprise:

Go up preparation photoresist layer (330) at described lower electrode layer (411), described photoresist layer pattern changes into a plurality of dikes to limit the bag on the described lower electrode layer.

8. according to the method for claim 7, wherein said precipitation reagent (320) is printed in the described bag.

9. according to the method for claim 7, wherein deposit described organic solution (300) by printing.

10. according to the process of claim 1 wherein that described device is an organic transistor.

11. according to the process of claim 1 wherein that described device is an organic solar batteries.

12. according to the process of claim 1 wherein that described precipitation reagent (320) comprises at least a in dioxane, propylene carbonate and the phenmethylol.

13. according to the process of claim 1 wherein that described precipitation reagent (320) comprises bivalent cation salt.

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